Environmental risks raised from the silver nanoparticles (AgNPs) release have attracted extensive attention of scientists with the rapidly increasing usage of AgNPs. Based on material flow analysis, the AgNPs released from the consumer products most possibly enter into wastewater treatment plants (WWTPs) through drainage pipeline system. Studies showed that the influent AgNPs might pose an adverse impact on microbial community structure, sludge properties, and performance of biological wastewater treatment system; however, there was little information about the effect and mechanism of AgNPs on biological phosphorus removal from wastewater and phosphate-accumulating organisms (PAOs). In the proposed study, advanced analyzing instruments, such as scanning electron micrograph, surface enhanced Raman spectroscopy, real-time quantitative PCR, and so on, will be used to systematically investigate the influence of AgNPs on the behaviors of pure PAO and performance of model biological wastewater treatment system. Besides, enzymatic activity analysis and molecular biology technologies will be used to reveal the mechanisms that AgNPs affect biological phosphorus removal from wastewater. The implementation of the project may deepen and extend the understanding of environmental behaviors and toxicology of AgNPs, and provide the basic data and references for the risk assessment of AgNPs.